数据结构-队列

队列：
含义：一个只能在队首进行删除，队尾进行插入的线性表，其特征是先进先出。
链式队列：
入队列：在对位插入
出队列：在对头删除
循环队列：

出现的原因是有可能发生满对列但是他又确实不是满的情况

package com.dataStructure.queue;

import java.util.Arrays;

public class MyQueue {
	private static int DEFAULT_SIZE = 10;
	private int capacity;
	private String[] datas;
	private int front;
	private int rear;
	//default array length to create empty queue
	public MyQueue() {
		this.capacity = DEFAULT_SIZE;
		this.datas = new String[this.capacity];
	}
	
	//create a queue by a initial element
	public MyQueue(String dataItem) {
		this();
		this.datas[0] = dataItem;
		this.rear++;
	}
	
	//create a queue by specified length and an dataItem
	public MyQueue(String dataItem, int specifiedLength) {
		this.capacity = specifiedLength;
		this.datas = new String[this.capacity];
		this.datas[0] = dataItem;
		this.rear++;
	}
	
	//Get Queue Size
	public int getQueueLength(){
		return this.rear - this.front;
	}
	
	//Check queue is empty
	public boolean isEmpty(){
		return this.rear == this.front;
	}
	
	//Insert data 
	public void insertData(String data){
		if(this.rear > this.capacity -1){
			return;
		}
		this.datas[this.rear++] = data;
	}
	
	//Remove from queue
	public String removeData(){
		if(isEmpty())
			return null;
		String oldData = this.datas[this.front];
		this.datas[this.front] = null;
		this.front++;
		return oldData;
	}
	
	public String element(){
		if(isEmpty()){
			return null;
		}
		return this.datas[this.front];
	}
	public void clear(){
		Arrays.fill(this.datas,null);
		front = 0;
		rear = 0;
	}

	public int getCapacity() {
		return capacity;
	}

	public void setCapacity(int capacity) {
		this.capacity = capacity;
	}

	public String[] getDatas() {
		return datas;
	}

	public void setDatas(String[] datas) {
		this.datas = datas;
	}

	public int getFront() {
		return front;
	}

	public void setFront(int front) {
		this.front = front;
	}

	public int getRear() {
		return rear;
	}

	public void setRear(int rear) {
		this.rear = rear;
	}
	
}

 

package com.dataStructure.queue;
/**
 * 循环队列出现的原因是有可能发生满对列但是他又确实不是满的情况
 * 从而为了避免这样的情况发生，导致数据不能插入
 * @author Administrator
 *
 */
public class LoopQueue {
	private static int DEFAULT_SIZE = 10;
	private int capacity;
	private String[] datas;
	private int front;
	private int rear;
	
	//default array length to create empty queue
	public LoopQueue() {
		this.capacity = DEFAULT_SIZE;
		this.datas = new String[this.capacity];
	}
	
	//create a queue by a initial element
	public LoopQueue(String dataItem) {
		this();
		this.datas[0] = dataItem;
		this.rear++;
	}
	
	//create a queue by specified length and an dataItem
	public LoopQueue(String dataItem, int specifiedLength) {
		this.capacity = specifiedLength;
		this.datas = new String[this.capacity];
		this.datas[0] = dataItem;
		this.rear++;
	}
	
	//Check queue is empty
	public boolean isEmpty(){
		return this.rear == this.front && getDatas()[this.rear] == null;
	}
	//Get Queue Size
	public int getQueueLength(){
		if(isEmpty())
			return 0;
		return this.rear > this.front ? this.rear - this.front : this.capacity-(this.front-this.rear);
	}
	//Insert data 
	public void insertData(String data){
		if(this.rear > this.capacity -1 && this.datas[0] != null){
			System.out.println("队列已满");
			return;
		}else if(this.rear == this.front && this.datas[this.front] != null){
			System.out.println("队列已满");
			return;
		}else if(this.rear > this.capacity -1 && this.datas[0] == null){
			this.rear = 0;
		}
		this.datas[this.rear] = data;
		rear++;
	}
	//Remove from queue
	public String removeData(){
		if(isEmpty())
			return null;
		String oldData = this.datas[this.front];
		this.datas[this.front] = null;
		this.front++;
		return oldData;
	}
	
	public String element(){
		if(isEmpty()){
			return null;
		}
		return this.datas[this.front];
	}
	public int getCapacity() {
		return capacity;
	}
	public void setCapacity(int capacity) {
		this.capacity = capacity;
	}
	public String[] getDatas() {
		return datas;
	}
	public void setDatas(String[] datas) {
		this.datas = datas;
	}
	public int getFront() {
		return front;
	}
	public void setFront(int front) {
		this.front = front;
	}
	public int getRear() {
		return rear;
	}
	public void setRear(int rear) {
		this.rear = rear;
	}
	
}

 

package com.dataStructure.queue;

public class Test {
	public static void main(String[] args) {
//		MyQueue queue = new MyQueue();
		LoopQueue queue = new LoopQueue();
		String book = "Java";
		String star = "Briteny Spears";
		String country = "China";
		String state = "Califonia";
		String name = "Tony";
		String name1 = "Tony1";
		String name2 = "Tony2";
		String name3 = "Tony3";
		String name4 = "Tony4";
		String name5 = "Tony5";
		String name6 = "Tony6";
		queue.insertData(book);
		queue.insertData(star);
		queue.insertData(country);
		queue.insertData(state);
		queue.insertData(name);
		queue.insertData(name1);
		queue.insertData(name2);
		queue.insertData(name3);
		queue.insertData(name4);
		queue.insertData(name5);
		queue.removeData();
		queue.removeData();
		queue.insertData(name6);
		queue.insertData(star);
		queue.removeData();
		queue.insertData(star);
		queue.insertData(star);
		System.out.println("Fornt :"+queue.getFront());
		System.out.println("Rear :"+queue.getRear());
		System.out.println(queue.getQueueLength());
	}
}